The present invention relates to a semiconductor device, and in particular, to a group II-IV semiconductor device having a p-type ohmic electrode structure which is suitable for the group II-IV semiconductor device.
Currently, blue light emitting diodes (LEDs) or blue laser diodes (LDs) have been made using a plural component group II-IV semiconductor which is higher than a ternary one and which contains zinc and selenium. In particular, with the use of a p-n junction which is formed by using nitrogen as a p-type dopant, suitable light emission can be obtained.
However, there are few metals suitable for use as a p-type ohmic electrode having a low resistance which is also suitable for use with p-type group II-IV compounds. Accordingly, the ohmic resistances of the p-layer side of green to blue light emitting diodes or semiconductor lasers having p-n junctions are extremely high. Accordingly, the majority of the power input into such an LED or LD is consumed in the form of heat, resulting in low efficiency of light emission with respect to input power. Further, the generation of heat can cause the devices such as LEDs or LDs to deteriorate, lowering their reliability. Accordingly, a satisfactory p-type ohmic electrode has been needed to obtain practically usable devices such as blue LEDs or LDs.
An object of the present invention is to provide a p-type ohmic electrode having low electric resistance for a p-type group II-IV semiconductor element containing zinc and selenium.